Studies of higher order visual dysfunction in schizophrenia indicate deficits in perceptual grouping/closure and correlated event related brain potential (ERP) abnormalities. Our broad goal is to determine the precise brain locations and neural processes that are indexed by these ERP abnormalities. The "Frame and Fill" Model of visual object processing provides a conceptual framework for this investigation. The model emphasizes a specific signal interaction; gross form/movement (M) information penetrates the brain systems very rapidly and sets-up or "frames" the neural processing of slower moving, (P) information that "fills-in" the fine detail and color of the object. The derivative hypothesis about schizophrenia is that the low level M system dysfunction, in addition to simply removing M mediated detail from the perceptual "picture", also damages a critical, higher-order "framing" operation, leading to failure in many basic aspects of object processing. This project will use the monkey as a model for the human. Our main recording method is to use dual multielectrodes (i.e., "paired recordings") to sample ERPs and action potentials from two brain regions simultaneously. This permits direct localization of ERP generators, definition of underlying physiological mechanisms, and evaluation of dynamic interactions between areas, Novel, single trial analyses will be critical in defining Neural Response Dynamics in each phase of the project. [unreadable] [unreadable] We have 3 SPECIFIC AIMS: 1-To determine how dynamic, dorsal-ventral stream interactions contribute to object processing and how their disruption degrades processing. 2-To define P, M and K contributions to higher order processing, and the consequences of disruption in one or more of these low level systems. 3-To identify cortical regions, and physiological processes generating object-related ERPs shown to be abnormal in schizophrenic patients. [unreadable] [unreadable]